The two great challenges of the 21st century are the battle against poverty and the management of climate change. On both we must act strongly now and expect to continue that action over the coming decades. Our response to climate change and poverty reduction will define our generation. If we fail on either one of them, we will fail on the other. The current crisis in the financial markets and the economic downturn is new and immediate, although some years in the making. All three challenges require urgent and decisive action, and all three can be overcome together through determined and concerted efforts across the world. But whilst recognising that we must respond, and respond strongly, to all three challenges, we should also recognise the opportunities: a well-constructed response to one can provide great direct advantages and opportunities for the other.

Twenty thousand people milling around thematic, country, commercial booths, attending political, learning, and topical sessions, watching musical and dance performances, and busily socializing in the hallways. All trying to work out how we can better manage water.

"Bridging the Divides" is the perfect name for this conference here in Istanbul. It's a city that links Asia and Europe, a city where many cultures have collided and where the religious buildings have housed worshipers and artifacts from different faiths.

Estimates assessing how many people will be displaced or forced to migrate because of climate change impacts are wide-ranging. But anecdotes of where climate-related migration is already taking place are beginning to crowd newspapers, radio and television programs, and various internet sources. Other than the low-lying islands which could be completely consumed by rising ocean waters, perhaps nowhere else in the world are these stories more pronounced than in Bangladesh.

In my first blog entry, I mentioned that adaptation to climate change spans a vast range of possible actions and that it can seem a rather abstract concept. Adaptation can range from sea walls to drought-resistant crops to social protection for climate shocks. This big range of possible actions makes it hard to nail down: what does any given country, region, or village really need to do to start adapting? Any two people talking about climate adaptation in poor countries probably carry different mental images of the kind of actions they think will be needed.

To pretend that we have all the answers—as some of the numerous reports being written on the topic do—is foolish. We are in the pioneer days of gearing up for climate change and no-one knows what actions will ultimately prove most effective.

As we talk to people around the world on some of the key findings and views that we're building into the next World Development Report, we encounter some heated debates. One of these much-argued points is our view that the world must aim to keep mean global warming below 2oC, but as one of our advisors says, "be prepared for 4oC".

Here are the reactions. Some (mostly, but not just, in Europe) find it shocking that we can even consider a world with warming above 2oC or with concentrations of CO2 at or above 550 ppm. Others worry that we are setting 2oC as a target, which is very sensitive in the context of the upcoming negotiations. We are not. We are simply agreeing in the light of mounting evidence that the world should try very hard to stay below 2oC, since losses will likely begin to rise rapidly above that temperature and irreversibe impacts may occur - particularly in developing countries. A new version of the "burning ember chart" makes this painfully obvious.

Climate change is not a new phenomenon. It has been around through much of Earth’s history. But what is new is the speed of climate change today and the growing certainty that it is a consequence of human actions. Why should poor and developing countries worry about climate change? Many say that it is a distant threat of uncertain magnitude and scale. With the global financial crisis, is it not more reasonable to address current priorities such as food security, unemployment, growth and burgeoning fiscal deficits?

Some readers and activists may question why the World Bank Group funds coal-fired power plants and yet professes to embrace sustainable development. The answer is that there is an urgent need for energy in the poor countries that we serve and indeed in my home country, China. There are roughly 1.6 billion people in developing countries--700 million of whom are in Africa and 550 million in South Asia--who lack access to electricity.